TY - JOUR
T1 - Kinship and sociality in coastal river otters
T2 - Are they related?
AU - Blundell, Gail M.
AU - Ben-David, Merav
AU - Groves, Pamela
AU - Bowyer, R. Terry
AU - Geffen, Eli
N1 - Funding Information:
We thank M. Gompper, H. Kruuk, E. Rexstad, and S. Jewett for comments on earlier drafts of this manuscript; K. Goodnight, J. Goudet, M. Henderson, and D.B. McDonald, for suggestions for analyses, software, or assistance with interpretation; and E. Debevec for assistance with statistical analyses. We thank L. Faro, P. Berry, S. Andersson, C. Durham, O. Ormseth, J. Faro, H. Kruuk, J. Balke, and C. Taylor for assistance in the field, and Alaska Department of Fish and Game biologists H. Golden and D. Rosenburg, as well as R. Stowell and M. Stowell for logistical support. We thank the crew of the M/V Babkin for assistance with field work in 1998. We thank J. Decreeft (Northwind Aviation), our radiotelemetry pilot, and J.A.K. Meier for GIS analyses. We thank J. Dallas and M. Fleming for providing microsatellite markers and T. LeCroy and D. Ziel for assistance with laboratory analysis of DNA. Funding was provided by the Exxon Valdez Oil Spill Trustees Council, the Alaska Science and Technology Foundation, Alaska Department of Fish and Game, the Institute of Arctic Biology, Alaska Cooperative Fish and Wildlife Research Unit, and the President’s Special Projects Fund at University of Alaska Fairbanks.
PY - 2004/9
Y1 - 2004/9
N2 - Previous studies of coastal river otters (Lontra canadensis) in Prince William Sound, Alaska, USA, documented atypical social organization for mammals. Social groups were composed largely of males, but some males remained solitary year-round and most females were asocial. Because, in carnivores, groups are usually composed of highly related individuals but group living also provides advantages unrelated to kinship, we concurrently evaluated the role of relatedness and ecological benefits in sociality among coastal river otters. By using DNA microsatellite analysis and radiotelemetry, we were able to reject the hypothesis that social groups of otters were kin based. In addition, we found no indication of kin avoidance, as would be expected from low dispersal and high local competition. Sociality conferred no reproductive benefits or costs to otters; number of offspring and number of relatives in the population did not differ between social and solitary animals. Solitary males were not older or larger than were social males, and there was no relation between male size and number of offspring, indicating that sexual selection did not mask a potential relation between sociality and reproductive success. Among coastal river otters in this region, sociality could be explained by the benefits obtained from cooperative foraging on high-quality schooling pelagic fishes. Such benefits did not require association with kin, resulting in no selection pressure for kin-based groups. The prediction that the degree of sociality in the population will fluctuate relative to the abundance of schooling pelagic fishes merits further investigation.
AB - Previous studies of coastal river otters (Lontra canadensis) in Prince William Sound, Alaska, USA, documented atypical social organization for mammals. Social groups were composed largely of males, but some males remained solitary year-round and most females were asocial. Because, in carnivores, groups are usually composed of highly related individuals but group living also provides advantages unrelated to kinship, we concurrently evaluated the role of relatedness and ecological benefits in sociality among coastal river otters. By using DNA microsatellite analysis and radiotelemetry, we were able to reject the hypothesis that social groups of otters were kin based. In addition, we found no indication of kin avoidance, as would be expected from low dispersal and high local competition. Sociality conferred no reproductive benefits or costs to otters; number of offspring and number of relatives in the population did not differ between social and solitary animals. Solitary males were not older or larger than were social males, and there was no relation between male size and number of offspring, indicating that sexual selection did not mask a potential relation between sociality and reproductive success. Among coastal river otters in this region, sociality could be explained by the benefits obtained from cooperative foraging on high-quality schooling pelagic fishes. Such benefits did not require association with kin, resulting in no selection pressure for kin-based groups. The prediction that the degree of sociality in the population will fluctuate relative to the abundance of schooling pelagic fishes merits further investigation.
KW - Alaska
KW - Kin selection
KW - Lontra canadensis
KW - Microsatellite DNA
KW - Reproductive success
KW - Schooling pelagic fishes
KW - Sexual selection
UR - http://www.scopus.com/inward/record.url?scp=4344704850&partnerID=8YFLogxK
U2 - 10.1093/beheco/arh110
DO - 10.1093/beheco/arh110
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AN - SCOPUS:4344704850
SN - 1045-2249
VL - 15
SP - 705
EP - 714
JO - Behavioral Ecology
JF - Behavioral Ecology
IS - 5
ER -